CN116347777A - Method for precisely controlling Stub length - Google Patents
Method for precisely controlling Stub length Download PDFInfo
- Publication number
- CN116347777A CN116347777A CN202310146809.4A CN202310146809A CN116347777A CN 116347777 A CN116347777 A CN 116347777A CN 202310146809 A CN202310146809 A CN 202310146809A CN 116347777 A CN116347777 A CN 116347777A
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- China
- Prior art keywords
- tin
- laser
- etching
- stub
- copper
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 34
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims abstract description 63
- 238000005530 etching Methods 0.000 claims abstract description 36
- 238000005553 drilling Methods 0.000 claims abstract description 33
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 29
- 229910052802 copper Inorganic materials 0.000 claims abstract description 29
- 239000010949 copper Substances 0.000 claims abstract description 29
- 238000007747 plating Methods 0.000 claims abstract description 17
- 238000004519 manufacturing process Methods 0.000 claims abstract description 8
- 238000010304 firing Methods 0.000 claims abstract description 4
- 239000007788 liquid Substances 0.000 claims description 9
- 238000005406 washing Methods 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 5
- 239000003814 drug Substances 0.000 claims description 5
- 238000003698 laser cutting Methods 0.000 claims description 4
- 238000002386 leaching Methods 0.000 claims description 4
- 238000005554 pickling Methods 0.000 claims description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 3
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 claims description 3
- 238000005520 cutting process Methods 0.000 claims description 3
- 238000000151 deposition Methods 0.000 claims description 3
- 238000009713 electroplating Methods 0.000 claims description 3
- 238000010030 laminating Methods 0.000 claims description 3
- 229910017604 nitric acid Inorganic materials 0.000 claims description 3
- 239000011814 protection agent Substances 0.000 claims description 3
- 230000008021 deposition Effects 0.000 claims description 2
- 230000009467 reduction Effects 0.000 claims description 2
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 12
- 230000006835 compression Effects 0.000 abstract description 2
- 238000007906 compression Methods 0.000 abstract description 2
- 238000010923 batch production Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910000679 solder Inorganic materials 0.000 description 2
- 241000530268 Lycaena heteronea Species 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
- H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
- H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process
- H05K3/067—Etchants
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
- H05K3/42—Plated through-holes or plated via connections
- H05K3/429—Plated through-holes specially for multilayer circuits, e.g. having connections to inner circuit layers
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- ing And Chemical Polishing (AREA)
Abstract
The invention discloses a method for precisely controlling the length of a Stub, which comprises the following steps: manufacturing a PCB; plating copper and tin on the whole plate; firing tin by laser; z-direction etching, and precise control of the length of the Stub is realized. The invention replaces the traditional back drilling process by combining the laser tin burning and the Z-direction etching, the whole process has no interference of compression uniformity and plate warpage, the processing precision can reach 0.001mm, which is more than 5 times of the depth control precision of the traditional back drilling, and the requirement of precisely controlling the length of a Stub in the processing process of an ultrathin medium can be met.
Description
Technical Field
The invention belongs to the technical field of printed circuit board processing, and particularly relates to a method for accurately controlling a Stub length.
Background
With the increasing transmission of data, the influence of through hole Stub (Stub) on the high-speed transmission of data is greater and greater, and the removal of the through hole Stub in the prior art mostly adopts a back drilling process. The back drilling process is a special manufacturing process, and specifically, a drilling machine is used for removing a copper layer on the hole wall at one end in the metallized through hole, so that one end of the hole wall in the through hole is free of copper, and the other end of the hole wall is provided with copper.
At present, the back drilling processing precision of the ultrathin core plate position is greatly influenced by plate thickness tolerance, uniformity thereof, back drilling equipment tolerance and the like, and the back drilling needs to drill through a target layer and cannot drill through a signal layer. In consideration of extremely poor plate thickness and equipment back drilling precision, a certain Stub length is required to be reserved in order to ensure that a production target layer is not drilled through to cause open circuits, and the requirements on accurate control of the Stub length are extremely high. However, the current high-frequency high-speed printed circuit board is affected by wiring and stacking in the laminated design, the thickness of the dielectric layer is thinner, and the thickness is only 0.075-0.1mm, so that the thickness exceeds the processing capability for back drilling precision. The best precision of back drilling can achieve +/-0.05 mm, but the precision of back drilling for batch production is greatly reduced due to the influence of lamination uniformity and plate warping, and the precision of batch back drilling can only achieve +/-0.1 mm and cannot meet the back drilling requirement of ultrathin media.
Disclosure of Invention
Aiming at the problem that the precision of back drilling of the existing PCB ultrathin medium is difficult to meet the requirement, so that the precision of the length of the Stub cannot be controlled accurately, the invention provides a method for controlling the length of the Stub accurately.
In order to solve the problems, the invention provides a method for precisely controlling the length of a Stub, which specifically comprises the following steps:
manufacturing a PCB; plating copper and tin on the whole plate; firing tin by laser; z-direction etching, and precise control of the length of the Stub is realized.
Further, the PCB fabrication includes: cutting, transferring an inner layer pattern, etching an inner layer, prestack, laminating, drilling and copper deposition.
Further, the whole plate copper plating tin includes whole plate copper plating and whole plate tin plating.
Further, the whole plate copper plating includes: firstly, pickling the manufactured PCB, then electroplating copper on the whole PCB, then washing with water for the second time, and then pickling.
Further, the whole plate tinning includes: and (3) carrying out whole-plate tinning on the PCB subjected to acid leaching, and then carrying out secondary water washing.
Further, the laser tin burning includes: and calling GERBER data corresponding to back drilling in GENESIS software, making ring laser tin burning data on the basis of the aperture of downwards drilling in the original design, setting the overall enlargement of the outer aperture of laser tin burning in the ring laser tin burning data on the basis of the original downwards drilling aperture by 0.2mm, setting the overall reduction of the inner aperture of the laser tin burning on the basis of the original downwards drilling aperture by 0.15mm, drawing out a small circle with the original aperture reduced by 0.15mm to form a ring graph with the width of 0.175mm, outputting the data in CAD format to obtain the ring laser tin burning data required by laser cutting, and then using a laser cutter to make laser tin burning treatment with specific parameters.
Further, the Z-direction etching includes: the etching depth is calculated according to the etching rate by using the liquid medicine prepared from ammonia water and copper chloride as alkaline etching liquid, and the etching in the Z direction is completed.
Further, after the Z-direction etching is finished, the method further comprises tin stripping, and tin stripping liquid medicine prepared by nitric acid and copper protection agent is used for stripping the plate with Z-direction etching depth control, so that the length of the Stub is accurately controlled.
Compared with the prior art, the invention replaces the traditional back drilling process by combining the laser tin burning and the Z-direction etching, the machining precision can reach 0.001mm, which is more than 5 times of the depth control precision of the traditional back drilling, the requirement on accurate control of the length of a Stub in the machining process of an ultrathin medium can be met, the whole process of the invention is free from the interference of compression uniformity and warpage, and the PCB manufactured by the invention has the advantages of high yield and easier detection and control.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic flow chart of a method for controlling a Stub length according to the present invention;
FIG. 2 is a schematic diagram of the design of the ring laser solder burning data according to the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
Referring to fig. 1, fig. 1 is a flow chart illustrating a method for controlling a Stub length according to the present invention. The invention provides a method for precisely controlling the length of a Stub, which specifically comprises the following steps:
a. a PCB front flow, which is manufactured by referring to a PCB multi-layer board flow;
the PCB front flow is manufactured by referring to the existing PCB multi-layer board flow and comprises the processes of cutting, transferring an inner layer pattern, etching the inner layer, prestack, laminating, drilling, depositing copper and the like, and the PCB front flow can be manufactured through the processes.
b. Copper and tin are plated on the whole plate, the copper thickness meets the requirement of hole copper, and the tin thickness is 3-5um;
in this embodiment, the whole plate copper plating tin includes two steps of whole plate copper plating and whole plate tin plating, wherein the whole plate copper plating includes: firstly, taking the PCB with the pre-process completed in the step a out of a plate raising groove, carrying out plate feeding and acid washing, then carrying out plate-finishing copper electroplating, then carrying out secondary water washing, and then carrying out acid leaching. In this embodiment, parameters of electroplated copper are set according to the plate thickness and the minimum aperture, so that the hole copper meets the requirements.
Plate tinning is performed after plate copper plating, and includes: carrying out whole-plate tin plating on the PCB subjected to acid leaching, so that the tin thickness reaches 3-5um; and then carrying out secondary water washing.
c. Laser tin burning, namely adopting specific data as laser tin burning;
as shown in FIG. 2, FIG. 2 is a schematic diagram of the design of the ring laser solder burning data according to the present invention. In the figure, 1 represents a copper layer designed in the tin burning data, 2 represents a tin layer designed in the tin burning data, and 3 represents a region where laser tin burning is required in the tin burning data.
The laser tin burning in this embodiment includes: firstly, calling GERBER data corresponding to back drilling in GENESIS software, making ring laser tin burning data on the basis of the aperture (H in fig. 2 represents the drilling aperture) needing to drill downwards in the original design, wherein the outer ring aperture (C in fig. 2 represents the outer ring aperture, which is designed to be 0.2mm larger than H) of laser tin burning data is integrally enlarged by 0.2mm on the basis of the original drilling aperture, meanwhile, the inner ring aperture (S in fig. 2 represents the inner ring aperture, which is designed to be 0.15mm smaller than H) of laser tin burning data is integrally reduced by 0.15mm on the basis of the original drilling aperture, and a small circular shape with the original aperture reduced by 0.15mm is drawn out, so that a ring chart with the width of 0.175mm is formed, outputting the data into a CAD format, obtaining the ring laser tin burning data needed by laser cutting, and then using a laser cutter to make laser tin burning treatment with specific parameters, and positioning the periphery to be fool-proof.
The dual-platform laser cutting machine is used for manufacturing laser tin burning, laser tin burning data is led in, a plate to be tin burned is positioned by a directional hole, a tin layer at a local specific annular position is removed by laser tin burning, and other positions are protected by tin, so that the effect of etching depth control can be achieved, wherein laser parameters and cutting software parameters of the laser tin burning are as follows:
d. and etching in the Z direction, controlling the depth in the Z direction according to the etching rate, realizing the accurate control of the length of the Stub, firstly using liquid medicine prepared from ammonia water and copper chloride as alkaline etching liquid, calculating the etching depth according to the etching rate, and completing the etching in the Z direction. Then, the tin stripping liquid medicine prepared by nitric acid and copper protection agent is used for stripping tin from the plate subjected to Z-direction etching depth control, so that the length of the Stub is accurately controlled.
In the embodiment, a laser tin burning and Z-direction etching method is adopted, the depth control precision is high, the Z-direction etching precision is generally calculated by taking 0.001mm as a unit, the precision can easily meet the requirements of +/-0.01 mm, the concentration control of back drills is generally calculated by taking 0.01mm as a unit, samples are not easy to control to +/-0.05 mm, the back drill precision of batch production is influenced by pressing uniformity, plate thickness uniformity and plate warpage, the precision can only achieve +/-0.1 mm, and the laser tin burning and Z-direction etching is 5 times of the back drill depth control precision. In addition, by adopting a method of laser tin burning and Z-direction etching, the difficulty of processing products is improved, the processing precision of laser tin burning and Z-direction etching can meet the requirement that the thickness of all the current dielectric layers is controlled, and the embodiment can achieve targeted depth control aiming at the condition that the thickness of the current multi-layer high-frequency high-speed material dielectric is 0.075-0.1 mm. Whereas the back drilling process brings with it many uncertainties and potential quality risks for products with medium thickness of 0.075-0.1mm, due to critical or exceeding its process capability + -0.05 mm. In addition, the method of laser tin burning and Z-direction etching is high in consistency, high in yield, easy to control and convenient to detect.
The embodiments of the invention have been described in detail above, but they are merely examples, and the invention is not limited to the embodiments described above. It will be apparent to those skilled in the art that any equivalent modifications or substitutions to this invention are within the scope of the invention, and therefore, all equivalent changes and modifications, improvements, etc. that do not depart from the spirit and scope of the principles of the invention are intended to be covered by this invention.
Claims (8)
1. A method of precisely controlling a Stub length, comprising the steps of:
manufacturing a PCB; plating copper and tin on the whole plate; firing tin by laser; z-direction etching, and precise control of the length of the Stub is realized.
2. The method of precisely controlling a Stub length of claim 1, wherein the PCB fabrication comprises: cutting, transferring an inner layer pattern, etching an inner layer, prestack, laminating, drilling and copper deposition.
3. The method of precisely controlling a Stub length of claim 2, wherein the full board copper tin plating comprises full board copper plating and full board tin plating.
4. The method of precisely controlling a Stub length of claim 3, wherein the whole plate copper plating comprises: firstly, pickling the manufactured PCB, then electroplating copper on the whole PCB, then washing with water for the second time, and then pickling.
5. The method of precisely controlling a Stub length of claim 4, wherein the whole plate tinning comprises: and (3) carrying out whole-plate tinning on the PCB subjected to acid leaching, and then carrying out secondary water washing.
6. The method of precisely controlling a Stub length of claim 5, wherein the laser firing tin comprises: and calling GERBER data corresponding to back drilling in GENESIS software, making ring laser tin burning data on the basis of the aperture of downwards drilling in the original design, setting the overall enlargement of the outer aperture of laser tin burning in the ring laser tin burning data on the basis of the original downwards drilling aperture by 0.2mm, setting the overall reduction of the inner aperture of the laser tin burning on the basis of the original downwards drilling aperture by 0.15mm, drawing out a small circle with the original aperture reduced by 0.15mm to form a ring graph with the width of 0.175mm, outputting the data in CAD format to obtain the ring laser tin burning data required by laser cutting, and then using a laser cutter to make laser tin burning treatment with specific parameters.
7. The method of precisely controlling a Stub length of claim 6, wherein the Z-direction etching comprises: the etching depth is calculated according to the etching rate by using the liquid medicine prepared from ammonia water and copper chloride as alkaline etching liquid, and the etching in the Z direction is completed.
8. The method of claim 7, wherein the method further comprises removing tin after the etching in the Z direction is completed, wherein the tin removing liquid prepared by nitric acid and copper protection agent removes tin from the plate with the depth controlled by the etching in the Z direction, thereby completing the accurate control of the length of the Stub.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310146809.4A CN116347777A (en) | 2023-02-22 | 2023-02-22 | Method for precisely controlling Stub length |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310146809.4A CN116347777A (en) | 2023-02-22 | 2023-02-22 | Method for precisely controlling Stub length |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116347777A true CN116347777A (en) | 2023-06-27 |
Family
ID=86886721
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310146809.4A Pending CN116347777A (en) | 2023-02-22 | 2023-02-22 | Method for precisely controlling Stub length |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116347777A (en) |
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2023
- 2023-02-22 CN CN202310146809.4A patent/CN116347777A/en active Pending
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